Evaluating the accuracy and large inaccuracy of two continuous glucose monitoring systems

Leelarathna, Lalantha, Nodale, Marianna, Allen, Janet M, Elleri, Daniela, Kumareswaran, Kavita, Haidar, Ahmad, Caldwell, Karen, Wilinska, Malgorzata E, Acerini, Carlo L, Evans, Mark L, Murphy, Helen R, Dunger, David B and Hovorka, Roman (2013) Evaluating the accuracy and large inaccuracy of two continuous glucose monitoring systems. Diabetes Technology & Therapeutics, 15 (2). pp. 143-149. ISSN 1520-9156

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Abstract

OBJECTIVE: This study evaluated the accuracy and large inaccuracy of the Freestyle Navigator (FSN) (Abbott Diabetes Care, Alameda, CA) and Dexcom SEVEN PLUS (DSP) (Dexcom, Inc., San Diego, CA) continuous glucose monitoring (CGM) systems during closed-loop studies. RESEARCH DESIGN AND METHODS: Paired CGM and plasma glucose values (7,182 data pairs) were collected, every 15-60 min, from 32 adults (36.2±9.3 years) and 20 adolescents (15.3±1.5 years) with type 1 diabetes who participated in closed-loop studies. Levels 1, 2, and 3 of large sensor error with increasing severity were defined according to absolute relative deviation greater than or equal to ±40%, ±50%, and ±60% at a reference glucose level of ≥6 mmol/L or absolute deviation greater than or equal to ±2.4 mmol/L,±3.0 mmol/L, and ±3.6 mmol/L at a reference glucose level of <6 mmol/L. RESULTS: Median absolute relative deviation was 9.9% for FSN and 12.6% for DSP. Proportions of data points in Zones A and B of Clarke error grid analysis were similar (96.4% for FSN vs. 97.8% for DSP). Large sensor over-reading, which increases risk of insulin over-delivery and hypoglycemia, occurred two- to threefold more frequently with DSP than FSN (once every 2.5, 4.6, and 10.7 days of FSN use vs. 1.2, 2.0, and 3.7 days of DSP use for Level 1-3 errors, respectively). At levels 2 and 3, large sensor errors lasting 1 h or longer were absent with FSN but persisted with DSP. CONCLUSIONS: FSN and DSP differ substantially in the frequency and duration of large inaccuracy despite only modest differences in conventional measures of numerical and clinical accuracy. Further evaluations are required to confirm that FSN is more suitable for integration into closed-loop delivery systems.

Item Type: Article
Uncontrolled Keywords: adolescent,adult,blood glucose,blood glucose self-monitoring,type 1 diabetes mellitus,drug delivery systems,england,equipment design,female,humans,hypoglycemic agents,insulin,insulin infusion systems,male,reproducibility of results,retrospective studies,self care
Faculty \ School: Faculty of Medicine and Health Sciences > Norwich Medical School
Depositing User: Pure Connector
Date Deposited: 25 May 2016 17:01
Last Modified: 25 Jul 2018 12:14
URI: https://ueaeprints.uea.ac.uk/id/eprint/59062
DOI: 10.1089/dia.2012.0245

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